and risk and demographic information was obtained from personal interviews. In this cohort, 28 (12.4%) women were BRCA mutation carriers and among these carriers, 39.3% were BRCA1 and 60.7% were BRCA2 mutations. Mutation carriers were more likely to have a familial history of breast and ovarian cancer, high-grade cancers, and triple negative (TN) cancers. Prevalence of TN was 48.3% in BRCA carriers and 25.6% in non-carriers and was 67.7% in BRCA1 and 35.3% in BRCA2 carriers. Estrogen receptor (ER) negative cancer was significantly associated with

BRCA1 mutations, especially in those under 40 years of age. BRCA-related breast cancer in this Chinese population is associated with family history and adverse pathological/ prognostic features, with BRCA2 mutations being more prevalent but BRCA1 carriers having more aggressive and TN cancers. Compared to Caucasian populations, prevalence of BRCA2 mutations and TN cancer in BRCA2 mutation carriers in Chinese population are elevated. Keywords Breast cancer BRCA mutation Pathology Clinical features Chinese Abbreviations DCIS Ductal carcinoma in situ TN Triple negative cancer LVI Lymphovascular invasive ER Estrogen receptor PR Progesterone receptor

Introduction BRCA mutations are known to be related to breast cancers with distinct clinical and pathological features compared to sporadic breast cancers (Basu et al. 2008; Atchley et al. 2008). There are also known clinical and pathologic differences between tumors arising from inheritance of mutations of BRCA1 and BRCA2 genes (Chappuis et al. 2000). In addition, studies in Western literature report potential epidemiological, clinical, and biological differences in breast cancer between Asian and Caucasian populations (John et al. 2007, Fackenthal and Olopade 2007). These data highlight the need to determine clinical and pathological characteristics in BRCA carriers in different populations, since these differences may affect future risk assessment, treatment planning, and outcomes. To address these issues we report information from a multicenter study of Chinese high-risk patients residing in the Hong Kong Special Administrative Region of the People’s Republic of China (HKSAR) in Southern China. This study identifies clinical and tumor pathologic features of breast cancer related to BRCA mutation inheritance, compared to those without mutations, and compares cancers from BRCA1 and BRCA2 mutation carriers.

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Hereditary and High Risk Breast Cancer Programme ( www.HRBCP.org) from March 2007 to November 2008, were recruited prospectively. Based on the lower incidence of breast cancer in Asia cohorts, clinically high risk female patients who were included in this study; were defined as those who: (1) had at least one-first- or second- degree relative with breast and/or ovarian cancer, regardless of age; (2) were less than 50 years of age at diagnosis; (3) had bilateral breast cancer; (4) had triple negative (TN) or medullary type pathology; (5) had at least one relative with cancers other than breast and ovarian cancer that are known to be related to BRCA mutations; or (6) they were an ovarian cancer patient with a family history of breast cancer. A standard epidemiological questionnaire, including a detailed family history, was administered to patients and medical information, including pathology reports, was retrieved from the patient’s medical records. Information from the epidemiological questionnaire included age at breast cancer diagnosis, other cancers diagnosed in the patient, and a family history of breast, ovarian, and other cancers in first, second, and third degree relatives. In addition, the following were categorized as having been used or not used: alcohol; tobacco; contraceptive pills, patches or injections; hormone replacement treatments; and infertility medications. Women were also asked if they had ever been pregnant and breast fed any child and if they were pre- or post-menopausal. Eligible patients were offered BRCA counseling and testing, and were consented for genetic testing and blood and tumor collection. Patients who tested positive for a BRCA mutation were asked to help recruit their first-degree relatives, who were also offered testing. This project was approved by the Ethical Committees of all the participating hospitals and centers in Hong Kong. BRCA mutation detection by conventional DNA sequencing and MLPA BRCA1 and BRCA2 mutation detection was performed on genomic DNA extracted from peripheral blood samples or paraffin embedded tissues, as described previously (Kwong et al. 2008). Mutation analysis was performed by direct DNA sequencing of all coding exons of BRCA1 and BRCA2 and multiplex ligation-dependent probe amplification (MLPA) (Sellner and Taylor 2004; Hogervorst et al. 2003; Schouten et al. 2002, Bunyan et al. 2004).

Materials and method

Clinical and pathological assessment

Patients

Clinical and pathological features included in the analysis were abstracted from medical records. These factors, related to extent of cancer at diagnosis and to treatment and prognosis, include: (a) type of breast cancer (in situ or

invasive); (b) grade (1–3, with lower numbers indicating more normal looking and slower growing cancers); stage (measure of extent of disease using the TNM system); (c) tumor size (T0, no tumor or in situ, sometimes classified as Tis, T1 = \ 2 cm, T2 = 2–5 cm, T3 = [ 5 cm); (d) lymph nodes (N) (N0 = no spread to nodes, N1 = 1–3 nodes, N2 = 4–9 nodes, N3 = [ 9 nodes plus other criteria); (e) metastasis to distant organs (M0 = no spread, M1 = spread to other organs); (f) lymphatic invasion (LVI), which is usually detected from tumor on prepared slides; (g) Ki67, an index (%) measuring a cancer antigen found in dividing cells; and (h) three receptors related to tumor cells accepting or rejecting estrogen (ER), progesterone (PR), or HER2/neu, all of which tend to fuel growth of breast cancer and are determinants of treatment and prognosis. The final measure is ‘‘triple negative’’ cancer, which are tumors that are ER-, PR-, and HER2-. The ER/ PR scoring is performed by the Allred scoring system in which comprised of proportion score and intensity score. The proportional score (i.e. % of positive cells) is: 0, completely negative; 1, \1/100; 2, 1/100–1/10; 3, 1/10–1/ 3; 4; 1/3–2/3 and 5, [2/3. The intensity score is: 0, negative; 1, weak; 2, intermediate and 3, strong. The total score is the sum of both and a score of [2 is considered positive. The HER2 criterion is based on ASCO/CAP guideline 2007. HER2 positive is defined as IHC3? and if 2? will reflex to FISH and categorized as HER2? for a ratio of [2.2 (HER2 to chromosome 17 ratio) on dual colour system. A HER2 negative result is defined as IHC 0 or 1? (Allred et al. 1998).

Statistical analysis Chi Square (X2) test was used to determine differences in characteristics among mutation carriers and non-carriers and between BRCA1 and BRCA2 carriers, with P-value of 0.05 or less being statistically significant, when data were categorical (Fisher’s Exact test was used where counts were less than five). Linear by linear associations were used when data were ordinal. A case–control analytic approach was used to estimate the odds ratios of demographic, behavioral, clinical, and pathological variables being associated with carrier status and, if a carrier, being a BRCA1 or a BRCA2 carrier. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using logistic regression models (SPSS 16.0, SPSS Inc, Chicago, USA). Univariate (unadjusted) models were used since multivariate analyses were limited by small sample sizes. However, where multivariate models were possible the OR’s were similar to the univariate models.

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Results Risk factors A total of 226 female patients who met the criteria for being at high risk for breast cancer were tested for BRCA mutations and 28 (12.4%) were mutation carriers, of which 11 (39.3%) were BRCA1 and 17 (60.7%) were BRCA2 mutations. Fifty (22.1%) of these women had bilateral breast cancer; 32.1% among BRCA carriers and 20.7% among non-carriers. The median age at diagnosis of breast cancer was 42 years (range 21–82). Seven patients also had ovarian cancer and their median age at ovarian cancer diagnosis was 49 years (range 23–65). All patients were Chinese of which 84% originated from Guangdong province of Southern China. The majority (69.3%) was born in Hong Kong but over 70% of their parents were born in Mainland China. When all patients was categorized into those less than age 40 and 40 or above, 55.6% of BRCA mutation carriers had breast cancer diagnosed before 40 years of age, compared to 36.0% of non-carriers, which is statistically significant at P = 0.05 and has an OR of 0.45; CI, 0.20–1.02 (Table 1). Our data also shows that BRCA carriers were 10 times more likely to have also been diagnosed with ovarian cancer (4/28; 14.3%) than non-carriers (3/198; 1.5%) (OR, 10.83; CI, 2.29, 51.34; P = 0.005). Only one ovarian cancer was seen in patients less than 40 years of age and she was in a mutation carrier. BRCA carriers and noncarriers did not differ for any of the other risk factors shown in Table 1 (use of alcohol, tobacco, contraceptive pills, infertility drugs, and hormone replacement therapy, having breast fed; and being menopausal); Although there is no statistically significance, mutation carriers were twice as likely to those who never have been pregnant as noncarriers (OR, 0.50; CI, 0.23–1.12.; P = 0.09). Family history and age BRCA mutation carriers were three times more likely to report family history of any cancer than non-carriers (OR, 3.05; CI 0.88–10.51) but this did not reach a significant difference (Table 2). BRCA carriers were statistically more likely to have relatives with breast cancer (OR, 2.99; CI, 1.29–6.93; P = 0.01) and ovarian cancer in family members (OR, 5.13; CI, 1.70–15.47; P = 0.002), compared to non-carriers. Furthermore, there was also statistically significant in linear relationship between the number of family members with breast cancer for BRCA carriers and non carriers, when looking at any family member (1st, 2nd, and 3rd degree relatives) with breast cancer (OR? (1 vs. 3), 25.6;

CI, 4.88–134.37) or only considering 1st degree relatives (OR? (1 vs. 2), 25.00; CI, 2.87–218.18). No statistical difference was seen for 2nd degree relatives. Twenty-two of the women with breast cancer were from families with both breast and ovarian cancer; 32% of BRCA carriers and 7% of non-carriers (data not shown). Of those with a family history of other malignancies, the most common were lung, colon, liver, nasopharyngeal, gastric, esophageal, and

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pancreatic cancers (data not shown), but there were no statistical difference between carriers and non-carriers. Mutation carriers were more likely to have family members with breast cancer when stratified by age (Table 3). This association was seen in both age groups, but was only statistically different when the age group was over 40 (OR, 3.75; CI, 1.01–14.51; P = 0.04). The opposite was true for a family history of ovarian cancer where carriers age 40 or

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Table 2 Association of BRCA mutation carriers and non-carriers and family history of breast and ovarian cancers BRCA Mutations Carriers (N = 28)*